Practical Scanning (in ppt format)

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Practical Scanning
for your Photographs
A “hands-on” demonstration of
scanning techniques for the typical
domestic environment - using the JPEG
format to save the finished work
JohnIGoodwin
1
Practical?
• Only about four actual scans to be performed,
but with explanations given as to HOW to setup each scanner to produce down-to-earth
results
• The scanning techniques have been simplified
to provide a mechanism for a typical user to
scan his entire collection of pictures in a
reasonable time and minimum costs
JohnIGoodwin
2
Matters not addressed
• I’m going to address photographic material
only
• Scanning documents is very similar to
scanning printed photographs, but any
presentation on this would need to go on to
include scanning over-sized documents,
optical character recognition, PDF production,
and document storage systems
JohnIGoodwin
3
The Fundamental Issues !!!!!
•
•
•
•
•
1. Objective
2. Resolution
3. Bit-depth
4. File Format
5. Monitor display NOT WYSIWYG
JohnIGoodwin
4
Let’s be Realistic
• Your photographs aren’t masterpieces that will be offered for
sale via a library
• You probably have ‘hard copies’ already – so are unlikely to
wish to print them again
• The results will likely as not be viewed directly from your
monitor where the resolution is a mere 72 pixels per inch
• You don’t want to buy a series of hard disks – and keep these
backed-up - to contain images of excessive sizes
• Your cameras probably generate just JPEG format images, and
you apparently find those results acceptable
• When you used colour negative film, you probably chose one
that accentuated the colours – not one that gave pastel
shades
• If you accept these statements, then JPEG is almost certainly
JohnIGoodwin
5
adequate for you.
Books on Scanning?
• Unfortunately, just about every book ever written supposedly
about scanning, is largely useless - because they don’t
highlight the important issues and arrange the material
logically
• “User manuals” supplied by ALL scanner manufacturers and
ALL suppliers of the software are totally useless
• Such as are written rarely attempt to EXPLAIN any of the
important topics; they all seem to assume that understanding
the scanner is beyond the capabilities of almost everybody
• I have found only two books that explain the issues
adequately:• 1)Scanning Negatives & Slides – by Sascha Steinhoff c £40
• 2) Mastering Digital Scanning – by David D. Busch c £40
• I haven’t found any other book worth purchasing; the first is a
JohnIGoodwin
6
bit more technical than the second
User Instructions for Scanners
• Every one that I’ve ever read was grossly inadequate
• File types and bit information were never addressed
• Everything was grossly over-simplified to almost the
level of ‘put the object on the platen and push the
button’
• Most scanners can be driven by a stand-alone
external driver OR by using a TWAIN-compliant driver
from within a photographic application; there are
advantages and disadvantages of each method
• Do READ the instructions before using. Some flatbed
scanners with slide attachments that plug-in, may
work only when used with the supplied application
JohnIGoodwin
7
TIFF or JPEG formats?
• Undoubtedly, the TIFF format produces the
“best” results in terms of quality – but at a
considerable cost in terms of the financial
outlay - and especially the time taken
• If you can produced “finished” work as you
scan, or are prepared to rescan particular
items if and when necessary to obtain a more
detailed result, then JPEG images will suffice
for most other purposes
JohnIGoodwin
8
Scanner Interfaces
• Mostly different for every model produced by every
manufacturer
• Some of these differences includes settings expressed in
Pixels, OR D.P.I (dots per inch), OR Samples per inch OR
physical sizes for printer results.
• A ‘common interface’ (of sorts) is available from SilverFast, at
a ridiculous price, and modules for different machines are not
available separately
• The programmes ‘VueScan’ & VueScan Professional are
available separately; this covers almost any scanner ever
made, including some not listed within; this includes RAW
TIFF files, and colour profiling; will not support special
features unique to a specific machine; it’s available at no cost
from ‘The Pirate Bay’ etc. via a ‘Torrent’ programme.
JohnIGoodwin
9
What is TIFF
• It is the “master” format from which all other photographic formats
(except BMP images, that are actually Internet format) have been derived
• At its’ most detailed, it can capture the “RAW” data from a scanner,
enabling all possible manipulations to be performed at some later date; as
soon as a departure is made from this RAW data state, then limitations
become imposed as to what changes will subsequently be possible –
without having to re-scan the original image
• However, there are many different formats of TIFF in use, in which less
detail is captured – resulting in the reduction of possibilities of making
later changes
• Most photographic libraries will insist that work be submitted in a
particular TIFF variant as specified by them
• The ‘File TYPE’ of ‘.TIFF’ applies to almost all the variant formats, and it
isn’t possible to tell what the actual characteristics are for and given file,
other than by opening from within Photoshop etc. and making deductions.
JohnIGoodwin
10
What is JPEG?
• It was derived from TIFF!
• It really isn’t a photographic format at all – it was an
expedient designed to support imaging on the Internet.
It compresses images very efficiently, to minimise file
sizes, and thereby reduces transmission times.
• You don’t get anything for nothing! The compression
process reduces the image quality, and the ability to
make later changes
• The JPEG format has been adopted for use with ‘basic’
cameras, whose users are apparently satisfied with the
results produced – BUT some size “errors” result
JohnIGoodwin
11
Disadvantages of using TIFF
• Scans will generally take longer to run
• Files generated could be up to FIFTY times
larger than an equivalent JEPG – with minimal
compression
• Much more storage space will be required to
keep the results and their back-ups
• You may need to get more sophisticated
equipment to produce fully-featured TIFF files
JohnIGoodwin
12
Disadvantages of using JEPG
• Colours recorded will be more ‘basic’ because an 8-bit (per channel)
system of recording colour is used
• Very limited adjustment to an image will be possible once saved in
this format
• The compression used will destroy some of the detail in the image
• Every time that an image is opened, AND RESAVED (even if no
changes made) – it is recompressed and so more detail lost
• After about five re-saves, the recompression will introduce visible
artefacts in the image
• If you were planning to scrap the original photographs, you may
need to reconsider that decision, just in case a re-scan is required at
some later date to recover the lost quality.
JohnIGoodwin
13
Advantages of using TIFF
• Greater variation of colours may be recorded
• There is more flexibility as to what may be
changed after the file has been created
• If the original has been saved as RAW TIFF, then it
may be practical to dispose of the original
photograph (however, continued development is
producing machines capable of producing even
better results, but prolonged storage of the
originals does not improve them).
JohnIGoodwin
14
Advantages of using JPEG
•
•
•
•
Lower cost of equipment
Quicker to produce
Much more practical to store the images
Gives similar results to those obtained by
snap-shotters cameras
JohnIGoodwin
15
Decision Time!
• JPEG would appear to have many advantages for the home
user, and using TIFF for an entire collection of photographs
is largely impractical
• Everything from now on in this presentation will be based
upon production of the final image as JPEG
• Specific Photographs that are required in further detail or
higher quality, may always be singled-out for special
attention – or re-scanned later
• Scanning to produce TIFF files, is essentially the same – but
using different settings on a scanner, and may require a
better quality of scanner (or process) to be used. The
scanning process would be considerably longer.
JohnIGoodwin
16
Making a Start
• Sort and clean the photographs. Discard any that
are too badly damaged to restore. Eliminate
‘duplicates’, and photographs of unknown
persons. Identify as many persons as possible in
unlabelled pictures, and attach your own labels
to the back. Enlist relatives to help in the
identification process
• Marry-up prints with negatives
• Separate out 1) unmatched negatives, 2)
unmatched prints, and 3) transparencies/slides
JohnIGoodwin
17
Types of Source Materials
• Reflective Materials – that is those that must
be viewed by shining light ONTO the surface
• Transparency Materials – that is those that
must be viewed by shining light THROUGH
them. Such materials may be either
NEGATIVES or POSITIVES (“slides”)
JohnIGoodwin
18
Reflective or Transparency
Methods ?
• When only a ‘print’ exists, there is no choice but to
process such by ‘reflective’ methods
• When both the print and a negative exist, then a
choice of using either the ‘reflective’ method of
‘transparency’ method exists. Technically, the
negative can produce the better result – but will you
actually notice the difference? (Try it and see!)
• If you have ‘Colour slides’, then you must use the
‘transparency’ method
JohnIGoodwin
19
Equipment Required
• Reflective materials can be scanned only by a flatbed
scanner. The prints are placed directly on the platen,
and the scanner illuminates them from beneath the
platen
• Transparencies can be scanned using a dedicated
slide scanner – but recently some flatbed scanners
are available that permit transparencies to be
processed, because they have an alternative means
of illumination within the scanner lid
• There are, however, photographic methods of
copying both prints and
transparencies
JohnIGoodwin
20
An Aside
•
•
•
•
•
•
Before we delve into the scanning process, lets us not overlook the ‘old’ methods
of copying prints and slides by conventional photographic processes – but
updating the operation by using a digital camera.
You would need a good quality “35mm” digital camera for the process, with either
some means of close focussing for reflective materials, and/or a slide copying
attachment
People that already have suitable equipment will not need to be told in detail just
how to use it
The close focussing lens/equipment does not need to be at all sophisticated, as the
focussing is done merely in two dimensions.
This process can produce results VERY much quicker than scanning, but the results
will not be of the same quality as that obtainable on quality scanners using high
resolution – but are you really going to notice any difference?
ION market several devices that can PHOTOGRAPH transparencies cheaply – but at
limited resolution; possibly sufficient for most users; these are NOT scanners
JohnIGoodwin
21
The ‘secret’ of getting a
good result from JPEG
• Scan in just as much (or little) detail as actually needed, make
any adjustments required (cropping, colour, brightness etc.) to
the quality of the image NOW, add the textual information –
THEN SAVE and don’t adjust again!
• Choose a level of compression that is not too great. Do
remember that by choosing to use JPEG, you will immediately
have lost half the detail originally available from the scan,
then loose a bit more (between 5% and 95% FURTHER)
depending upon the degree of JPEG compression chosen
• Scanning from WITHIN a good photographic editor, will
facilitate a greater level of control in the editing process than
available from just the scanner interface
JohnIGoodwin
22
Technical Terms
that Need to be Understood
• BIT-DEPTH – a means of controlling the degree of subtlety in
colours or greys. JPEG uses just 24-bit for colour and 8-bit for
greyscale, but you have to scan at 64-bit to utilise the dust
and scratch removal facility (even if saving as 24-bit). Claims
for greater numbers are simply fraudulent in order to sell
scanners
• RESOLUTION – a control over the amount of detail resolved,
generally related to the degree of enlargement possible.
Except on dedicated slide scanners where the maximum
(4,000?) should always be used; exceeding a resolution of 600
pixels for reflective images is rarely helpful, and apparatus
that claims to resolve beyond 600 is generally the subject of
fraudulent claims, or is in fact re-sampling the target many
JohnIGoodwin
23
times, thus taking a far greater time to complete the process
Channels?
• Understanding a discussion about bit-depth, can seem a trifle complicated
at first – but is really very simple.
• A optical instrument captures colour information by channel – there being
one channel for each of the colours RED, BLUE, and GREEN; GREYSCALE
uses but one channel, as does BLACK & WHITE; features such as Dust &
Scratch removal use a fourth channel – INFRARED, that is rarely explained.
• EACH channel carries data as either 8 or 16 bit, thus requiring a total of
typically either 24 or 48 bit structure to record a colour image – these
being either 3 x 8 or 3 x 16. Greyscale uses but one channel, so the data is
either 8 or 16 bit, whilst genuine ‘Black & White’ uses just 2 bits!
• When Dust and Scratch removal are applied, resultant images will be 64bit, because this is available ONLY in 16 bit mode, and furthermore the
infra-red channel content is rarely counted in any expression of the image
characteristics.
• Encountering other sets of numbers when using older equipment, occurs
because the makers may have used a 10,12, or 14 bit system instead of 16.
Such get “padded-out” to be stored as 48-bit.
• I have seen fraudulent claims forJohnIGoodwin
96-bit 6 colour images!
24
•
•
•
•
•
•
•
•
Enlargement
The scanning process has a general similarity to the silver halide process of
printing and enlarging a photograph
Any digital photographic image can normally be enlarged to only a certain degree,
after which the image degenerates into a series of rectangular blotches, once the
limitation of ‘actual pixels’ has been reached
One ‘cheat’ to increase image size, is called ‘interpolation’, and involves
‘multiplying-up’ the actual pixel data
The other ‘cheat’ is by “increasing” resolution by multi-sampling of the original
image
Both ‘cheats’ generally result in claims for “resolutions” that vastly exceed the true
optical resolution
Some of your “contact prints” when being scanned, may benefit to some extent by
selecting higher resolution settings, so as to produce an image large enough to fill
your computer screen automatically, but often images generally get “stretched” or
reduced to fill the screen
Some scanner interfaces will ask for a size setting to be made as if for printing,
rather than give an option to set the “resolution”
Slides/Negatives/Transparencies are normally scanned with “same size” settings
JohnIGoodwin
25
Previous “Scanner” Presentations
• I’ve given two presentations before – one on
selecting and buying a scanner, and the other on all
the file types and other technical terms involved. I’m
not endeavouring to repeat either here, so I’ve
placed copies of the presentations upon our website
for downloading.
JohnIGoodwin
26
Scanner Devices - Flatbed
• A “flatbed” scanner will be required for
scanning “print” images.
• Some flatbed scanners also have a lamp built
into the lid, plus devices intended to hold
transparency materials on the platten. Such
may be cumbersome to use, and generally do
not give as good as result as a dedicated slide
scanner – but their results may be good
enough for the purpose intended
JohnIGoodwin
27
Scanner Devices - Transparency
• A dedicated transparency scanner will be
needed to obtain the best results from
transparency (film) materials, but cannot
handle reflective materials at all
• Dedicated transparency scanners are quite
pricey, so you may need to consider a cheaper
solution involving a flatbed scanner, or
photographic method
JohnIGoodwin
28
Selecting the equipment
• This was covered in detail in an earlier presentation, so isn’t
being covered in detail here.
• Most flatbed scanners for sale will fraudulently claim
resolutions greatly in excess of the true resolution; check the
detailed specification to find the true optical resolution
(generally 600 pixels); if the optical resolution isn’t mentioned
anywhere, then the claims are obviously fraudulent – so do
not purchase.
• Transparency scanners generally quote their specifications
truthfully, but the same caveat still applies, and price is very
often a tell-tale. New equipment should have a genuine
optical resolution of 4,000 pixels.
• Specifications shewn on the packaging, frequently overstate
the equipment capabilities by including the results of
interpolation and multi-scanning.
JohnIGoodwin
29
Transferring scanned data
• Scanning produces really VAST amount of data to be
transferred to your computer. We are talking about 1,000s of
millions of bits of data (that’s billions to the uneducated)
• You MUST have a FAST interface to perform a scan, and must
not accidentally degrade it.
• By correctly trimming the areas to be scanned and setting the
required resolution appropriately, and orienting the target
most efficiently, the scanned time may be kept to a more
reasonable level. Scanned times could well exceed 15
minutes without due care taken.
JohnIGoodwin
30
Section Two
HANDS-ON SCANNING
JohnIGoodwin
31
Scan Session – 1 - Reflective
• Epson Perfection 3170 Scanner
• Lamp mounted in lid
• Slide holder supplied – but no holder for film
strips
• HP G4050 Scanner
• Lamp mounted in lid
• Both slide holder and
JohnIGoodwin
32
Notes
•
•
•
•
Connection – USB Firewire SCSI
USB2 v USB 1.1
Time taken to transfer data
Software interface – stand alone or
application
• Simple or advanced settings
• Focus imperfection - with film not in contact
• Mount film in oil?
JohnIGoodwin
33
Canon 2700F Slide Scanner
• Scans slides and negatives to 3,000 pixels
• Works with Vuescan
• Can handle slides individually, or uncut 35mm
film as strips, or APS cassettes
JohnIGoodwin
34
Notes
• Handles both positives and negatives
JohnIGoodwin
35
ION “Film 2 PC” Device
• This device is one of a series that sometimes
incorrectly claim to be scanners, and will turn a slide
or a negative into a digital image at 1800 pixels per
inch
• They are actually camera devices – similar to a
“webcam” that send an image of the slide to a PC,
transferring it into the supplied editor programme,
that can then make limited adjustments then save
the results as JPEG or perhaps TIFF
• Some versions of the ION devices merely save their
results directly to an SD card, and don’t connect
directly to a computer
JohnIGoodwin
36
Notes
• May not include a negative carrier in every
model
• This is a photographic method
• Versions that write to an SD card, have to have
their JPEG images modified – if necessary –
after the image is saved in the JPEG format
• Some versions include the ability to generate
both TIFF or JPEG images. The TIFF versions
are just 8-bit files, so no real benefit obtained
JohnIGoodwin
37
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